Modern hearing assistance devices, such as hearing aids, typically include digital electronics to enhance the wearer's listening experience. Hearing aids are electronic instruments worn in or around the ear that compensate for hearing losses by specially amplifying sound. Hearing aids use microphones (e.g., transducers) and other electro-mechanical components that are connected via wires to the hearing aid circuitry.
As hearing assistance microphones become smaller (e.g., MEMS microphones), it is becoming increasingly difficult to place a spout on them without sacrificing the size gains. The accepted method and design of hearing assistance microphones arranges a tube in axial alignment with (i.e., orthogonal to) the acoustic port of the microphone. However, this axial alignment configuration creates a direct line-of-sight path for environmental or biological hearing aid debris (e.g., cerumen) to fall into the microphone's internal components. Additionally, the connection between the orthogonal tube and the microphone acoustic port is subject to strain from tube deflection.
Some existing solutions have attempted to solve these issues with a blind tube, notched, welded in place, and epoxied in situ on the exterior of the microphone. However, matching the tube to the profile of the microphone greatly increases the possibility of slit leakage, and the thin wall of the tube limits the structural integrity of the mount and seal. Some existing solutions have attempted to address this issue by eliminating a spout or microphone port. However, using no port requires a face seal on the microphone that may be unreliable, and increases the sensitivity of the face seal to the variations in manufacturing tolerance found in microphone manufacture.
Some existing solutions require a barrier placed in the acoustic path after the spout. However, such a barrier requires the creation of a seal, and due the thin-wall nature of the method of manufacture, the seal may be prone to slit leaks or delamination during assembly. Additionally, thin-wall manufacturing requires an exterior wall or combination of walls, but these walls may be very sensitive to variations in manufacturing tolerances.
What is needed in the art is an improved system for reducing the amount of environmental or biological hearing aid debris that falls into the microphones internal components.